Electric time system with electronic self-regulation



Aug. 4, 1953 J. L. WAGNER ETAL 2,647,360

ELECTRIC TIME SYSTEM WITH ELECTRONIC SELF-REGULATION Filed June 28, 1949 5 Sheets-Sheet 1 m ca I Y 65% W INVENTORS JOHN L. WAG/VH2 WASHINGTON WEBB ATTORNEY ROBfRT M E/CHOK/V Aug. 4, 1953 J. WAGNER ETAL 2,647,360

ELECTRIC TIME SYSTEM WITH ELECTRONIC SELF-REGULATION Filed June 28, 1949 s Sheets-Sheet 2 INVENTORS JOHN L, WAGNER WASH/1V6 TO/V W555 EOBfET N [/C//0//V BY I ATTORNEY 1953 J. WAGNER ETAL 2,647,360

ELECTRIC TIME SYSTEM WITH ELECTRONIC SELF-REGULATION Filed June 28, 1949 5 Sheet$-Sheet 3 \NVENTORS JOHN L. WAGNER WASH/N6 TON WEBB ROBE/3 T N. [/Cl/OR/V ATTORNEY Aug. 4, 1953 J. L. WAGNER ETAL 2,647,360

ELECTRIC TIME SYSTEM WITH ELECTRONIC SELF'REGULATIQN Filed June 28, 1949 5 Sheets-Sheet;

RUN Z6 5 JOHN L. WA GIVE/Z WASH/NGTOV WEB A 0 ERT M E/C/{O/ZN BY J ATTORNE Aug. 4, 1953 J. L. WAGNER ETAL 2,547,360

ELECTRIC'TIME SYSTEM WITH ELECTRONIC SELF-REGULATION Filed June 28, 1949 s Sheets-Sheet 5 ti Tia- JOHN L WAGNER WASH/NGTO/V WE B5 ROBE/3T N 'E/C/IORN W/7, ATTORNEY Patented Aug. 4, 1953 'UNITED S -PATENT OFFICE ELECTRIC-TIME SYSTEM WITH ELEC- 'IRONIGv SELF-REGULATION John. L V'Wa'gner; Endwell, Washington Webb, Endicottyandllbbat N i -Eich'orn, Vestal, N; Y.,

i assignors to"International Business Machines Gorporation, New York, J N. Y.,. a. scorporation Application 11111628, 1949;S'eria'l N0.101,884

1 2-'Glaims.. (,Cli' 58--'-J35) This invention relates'to a system for actuating secondary clocks by a master clockto maintain all of the clocks inthe' systemin'sync'hronism with the master clock. The present invention is'directed .to" synchro- 'nization of secondary clocks or"the:'operation of signal units under the control of amasterclock by the agency of electrical ene'rgyyand has for its object to utilize for thatenergy a; high flB- quency signal.

-Another object is to produce electronically operated clock synchronizing system involving the use of as few Wires as possible.

This particular clock system comprises "means for impressing accurately controlled time signals of a high frequency upon a commercial'electric light and power system,. which power system serves as the transmission medium,andhaving means connected to the power'system' for receiving said signals, that means utilized tosynchronize any number of remotely 'situatedisecondary clocks or energize any number of signal units,

such as bells, buzzers, horns, etc.

' The operation of the system is accomplished by a master clock which periodicallyenergizes an electronic transmitter and causes itto transmit a signal. In the preferred program, thesignal is transmitted once each hour for a duration of four seconds beginning twoseconds beforeand ending two seconds after the fifty-eig-hth'minute.

The transmitter is connected to thelocaliialterhating current lighting system. ahditstransmitted signal is available throughoutlthesystem y selective tuned receiving. unit which is connected thereto. 'E'ach secondary. clock is equipped with a receiver, withinwhich the. signal ondary clocks are in agreement with the-master clock, they will be unaffected by thesignalyhowever, if they are approximately fiitynineininutes slow to fifty-five seconds fast at the fifty-eighth .'minute, they will be correct :at-thefifty-ninth 1 minute. In the absence of the signaLflthe-secondary clocks will operate as normalclocks.

Should the secondary clocks bemorethanfiitynine minutes slow, provision is made fontrans- ""mitting a signal once .each minute which. will move the clocks ahead one hour on the reception of each signal.

*The master clock can also cause the operation of audible signals in a similar manner. "The frequency of the signal-used in this application will usually be different than the synchronizing signal since it'probably would not be desirable to operate audible signals at the time selected -"-'for--synchronizing clocks.

The receiver circuits are-essentially the'same, except that the audible "s'ignal unit itself rather than a clutch magnet is energized. Gtherobjects of the invention will be'pointed out-in thefollowing description and claims'and illustrated in the accompanying drawings; which disclose, by way of example, the principle'of the invention and the best mode, which has been contemplated, oi-applyin that principle.

In the drawings: Figs. 1, 2, 3, 4 and 5 illustrate typical applications "of' theelectronic self-regulation andsignal system.

,Fig'. 6 is a wiring diagram of components contained in the master clock and. transmitter.

Figs. 7 and 8 are diagrams of the receiver circultshsedinthe secondary clocks and signal units, respectively.

In Fig; 1 a step-down transformer II is interposed'between a local supply power circuit 2 and a 'high distribution bus [2.

The local supply circuit furnishes power to all sorts of common power utilization devices, such as lamps 'l3'and motor 14. A master clock I, similar to thetype disclosed in the application of R. B. Johnson 'et al.,' SerialNo. 990, filed January '7, 1948, is con- 'nected to a source'of energy 3, which source may be thelocal power circuit. Master clocks of this type.'are equipped with contacts that are cam .operated to close at certain intervals. These contactsareiutilized in. this instance to energize through control lines t a transmitter 5 which is connected to asource of energy 1, andagain the "sourcemay be the local'power circuit. When -i'energ'ized; the transmitter sends a high frequency signal; through a line coupling sectionii, to the local power circuit, which circuit then acts as the tr'ansmitting medium.

Signal units Band 9 and secondary'clocks'dfl,

"each of which hasan associatedtuned receiver, are connected to the power sysem. On reception .of. the signal of their respective receivers, either "the secondary clocks will be synchronized or'the signal unit Willv be energized. The secondary iclocksmay be.of the type disclosed in the appli- "cation of. C; Larrabee, Serial No. 5,447,, filed "January '30, 1948, now Patent No. 2,569,815,

granted October 2, 1951, which clock has a me- 3 chanical means of time delay so that, as previously mentioned, transient currents will not cause any undesired operation. The receiver circuits of the signal units also provide a time delay, the composition and operation of which will be discussed later.

In Figs. 2 and 6, a three-phase system, Y connected with a grounded neutral is illustrated. In both figures the master clock and the transmitter are shown obtaining energy through input lines 3 and I respectively, connected across legs of the Y, that is, across terminals of the Y and the grounded neutral.

The transmitter is of relatively simple construction (see Fig. 6), being composed of a rectifier, an oscillator and a push-pull amplifier. The power circuit is completed to the full wave rectifier 42 from the three-phase power system 33 through the contact 32A and the transformer 65 which includes a winding 43 for furnishing power to the tube filaments. A filter network 44 composed of capacitors S6 and resistors 4? smooth the pulsating D. 0. current. The rectified voltage is applied, on closing of the keying relay contact 36A, to the plate of the oscillator tube 52, and to the screen grid of the amplifier tubes through the dropping resistor 58. The plates of the amplifier tubes are connected to the rectified voltage through parasitic suppressor resistors 59 and the primary winding of the output transformer 6|.

The preferred oscillator is a variation of the Hartley type using a pentode tube with the resonant circuit comprising the primary coil of a coupling transformer 55 and the tuning condenser The frequency of the transmitter may be changed by the closing of any one of the relay contacts 33A, 34A or 35A which will cause the inclusion of capacitors 5M1, 5E3 or 5! C in the resonant circuit. The resistor 53, in the grid circuit, aids in the stabilization of the frequency by isolating the tube capacity from the circuit capacity, while resistor 54, the cathode circuit, is used to create the proper bias.

The oscillator output is coupled through transformer to an amplifier stage of four beam power tubes operating in push-pull parallel. Bias for the amplifier tubes is developed by resistor 56 and capacitor 57 while capacitor 49 is a screen by-pass. The transmitter output appears across the output transformer 65 which is tuned by the capacitor 69. The output is coupled through the line coupling section 6, consisting of coupling capacitors 63 and the safety bleeder resistors 62, and through the switch 39 to the local three phase power system 38.

Operation of the transmitter is controlled in the following manner. The master clock components including the control motor 15 and the winding motor l6, obtain power directly from the power lines. A transformer i1, also connected to the power lines, steps down the voltage to the proper value for the control circuits. Relay 32, which connects power to the transformer 48 in the transmitter, is energized through contacts 22, which are closed by cam 24 as it revolves at least two minutes before it is desired to transmit a signal so that the tubes will be energized and have a chance to warm up before the transmitter is keyed. Further revolution of the cam 24 will cause closing of contacts 2 I, the function of which is to select the minute Within which it is desired to transmit the signal, so that on the next closing of contacts 29 by cam 23, the keying relay 3 8 is energized, and the transmitter is operated.

. audible signal units.

Contacts 20 are closed for the duration of four seconds each minute, which duration is the length of time that the signal is transmitted. The synchronization of the clocks thus usually takes place about once each hour and practical considerations make it desirable that the range of correction be limited to the values previously mentioned, approximately fifty-nine minutes slow to fifty-five seconds fast.

If the system is at all normal, that range of synchronization is more than sufficient for satisfactory operation, but there may be occasions when through a failure of one sort or another the secondary clocks may be off by as much as eleven hours. In that case, synchronization can be ac complished by turning the advance-run switch 26 t0 the advance position. If conditions are proper for transmitting, the relay 25 is operated which, in effect, shunts contacts 2i and 22. While those contacts are shunted, the transmitter will transmit the synchronizing signal once each minute as the contact 20 is closed. The secondary clocks will then be moved ahead one hour per minute until the switch 26 is opened. If the secondary clocks are eleven hours slow the switch 26 should be left in the advance position until the synchronizing pulse has been transmitted ten times. As the hands begin to reset the tenth time the switch should be thrown to the run position, so that during the next 58th to the 59th minutes, the regular correcting cycle, all clocks will correct to the proper time. Cam operated contact H! can be used to prevent energizing of the relay 25, when the switch is thrown to the advance position, should circuit conditions be such that the transmitter should not be keyed. For example, it is necessary that the transmitter tubes be at the proper operating temperature at the time of transmission. To insure that the tubes have time to reach the proper temperature, cam I9 is programmed to close contact i8, for an instant, just subsequent to the time that contact 20 opens. Therefore, when the advance-run switch is thrown to the advance position, relay 25 will not be closed until the closing of contact E8. However, at that time, the relay 25 closes and remains closed, thus energizing the power relay 32, and thereby furnishing power to the tubes. The keying rela will not be energized until the next closing of contact 2? approximately fifty-six seconds later, which gives the tubes ample time to reach the operating temperature,

Provision is made in the circuit of Fig. 6 for three additional frequencies of transmission which frequencies are used in the operation of A programming motor 28, energized through switch 2? is synchronized with the clock movement and is used to drive several cams. Two of these cams (not shown) have a function similar to earns 23 and 24, that is to energize the transmitter, to select the minute of transmission, and to control the duration of the signal. Cams 29, 39 and 32 are utilized to change the frequency of transmission through contacts 29A, 33A and 3iA; relays 33, 34, and 3:3; and capacitors 5|A, MB and 550. All three of the circuits are identical so that the explanation of one will suffice. Cam 3! closes contact 31A, some time before keying of the transmitter, which energizes relay 35 placing capacitor MC in parallel with capacitor 5! to increase the capacitance of the tuned circuit and thus change the frequency of transmission. Of course not more than one frequency can be transmitted at one time but the program can be set to cause transmission of one znrafter."another -with:1ittl eor no lapse between. the

-;.;signals.

a The .receivermunits (see Figs. 7.and 8). utilize both series and; parallel .resonantcircuits. .The

series circuit which oifers,,a.:high.impedance to Lsixty.cycle,;current,-,,the usual .power line frequency, is composed ofv the. coil 65 and thecapaci- 1 tor, 66; A coilzfilywhichis inductively coupled rwith thecoilGE, is paralleledwith capacitor 68 toform a parallel resonant circuitat the signal frequency. u'Ihe voltage developed across that .ulatter. circuit .causesthe.cold.cathode tube,- 69 to f reacross. thestarting. anode :and cathode, which ..;ionizes the gasin .the tube andv permits a dis- ;z; charge of-the power frequency fromcathode to anode. The discharge. is..extinguished on the first negative cycle ofthe power frequency following ,the end of, the ,signal transmission. In the .receiver of the secondary clock (see Fig. '7), on the discharge from the cathode to anode of the tube, .a clutchmagnet is energized to start the self-regulating cycleof theclock. In the receiver of the audible signal unit (see Fig. 8), relay; H is energized, closing. its contact. 'llA, and

1; thereby. causing operation ofthe audible signal unit 8. The capacitor 13, connected in parallel with the relay coil H, and the resistor I4, are selected to provide a time delay in the operation of the relay. The time of delay is the time necessary after firing of tube, for the capacitor 13 to change through resistor 74 to a voltage suiiicient to cause operation of the relay 1 l The values of the components are selected so that the time is of the order of two seconds.

Fig. 3 is a diagram of a three-phase three-wire ungrounded delta system with the signal fed across phases. In this system, the signal voltage on the phase fed will be greater than that of the other two phases. However, the circuit will provide satisfactory operation across any phase since the amplification obtained in the receiver circuit is sufficient to fire the tube. It is not feasible to use this method if the power circuit makes use of power factor correction capacitors, since the capacitors connected between the phases would be a large load or the practical short for the signal frequency.

Fig. 4 is a diagram of a three-phase three-wire ungrounded delta system with the signal fed between phases and ground. The signal is fed from the transmitter 5 through the line coupling section 6 to the terminals of the delta connected secondary windings. Since the signal frequency on each phase is equal, no signal will be produced in the transformer. On the other hand, the signal will appear between each phase and ground. In order to both operate and synchronize the secondary clocks in this system, small transformers iii are used. The primary winding is connected across one of the power phases while the secondary is connected to the clock to be operated thereby completing the power circuit. Capacitors 16 are interposed between one or more of the power lines 2 and one side of the secondary of the small transformer, the other side of the secondary being grounded. The signal is thus transmitted over the power lines 2, through condensers l6, and through the secondary circuit of the transformers 15, including the clock or clocks to be synchronized, to ground.

A diagram of a three-phase, three-wire ungrounded delta connected system, having the signal fed between phases and ground, and having two or more transformer secondaries operated both separately: andpineparallel.-is=:-illustrated in uFig. 5.

' The operationiof .a-two+transformer:.powensystem I requirespthe .use :of disconnect breakersa 11 1 between the secondaries of 2 each;- ina. .order, -:that separate; operation willpbe.possible andwi'alsoto .act as a protective-.deviceswhen operating impar- .allel. When operating separately;:' in: is ;.neces- -sary to: furnish some means .to ,pass oncoupleathe signal frequency-from lonevcircuit. toanotherand yet not permitpassage ofrfthe, powen frequency.

impedance at ,thenihighgsignal frequency; Of

course, one power, circuit -;can-. .be, directly. con- -nected to the transmitter; in, the manner-sexplained above andillustratedin Fig. 4,-butjzany additional ,powerucircuits not operating in parallel will havetotbe coupled. Thenetwork; of

capacitors, used;inthisinstance is composed of three capacitors 18A. having loner side connected I to each terminal of thedelta system-neareststhe transmitter, andthree additional capacitorss18B having one side connectedto, eachaterminalg of the delta system to be coupled, while all six capacitors have their remaining sides in a common connection. Such a coupling network provides many advantages. In the event that one of the capacitors, either 18A or 183, develops a short, coupling of the signal frequency still takes place, theremaining capacitors having a low impedance at the signal frequency, yet the power frequency is blocked since there would still be at least one capacitor, offering high impedance to the power frequency, between the lines of the two systems.

If one of the capacitors 18A is open circuited, coupling of the signal frequency is made through the remaining capacitors 18A to the common connection and thence through the three capacitors 183 to each line of the second system. Thus, the full signal frequency can be obtained from each line of each system. However, if one of the capacitors (83 opens, while coupling takes place through the remaining capacitors, the full signal will not be present in the line directly connected to the open capacitor. The coupled circuit will be similar in operation to the circuit shown in Fig. 3, and while the signal on the one line may be reduced, the amplification will usually be sufficient to synchronize the clocks or cause operation of the signal units of the components connected to that line. The power frequency, of course, is blocked with greater effectivenesss by opening of any one of the capacitors.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In combination with a delta connected alternating current power supply line having load devices connected across phases thereof, a generator for producing signal impulses of frequency higher than that of the alternating current on said supply line, a ground connection, means for coupling said generator between said ground connection and each of the wires of said supply line, said last means including means to interpose a high impedance to said alternating current between said supply line wires and said ground connection, time controlled means for causing said generator to impress said signal impulses on all of the wires of said supply line through said coupling means in the same time phase, a synchronous-motor-operated time keeping device connected across a phase of said supply line, a receiver including circuit means selectively responsive to said impulses for controlling said time keeping device, means connecting said circuit means to ground, and capacitative coupling means for transmitting said signal impulses from all of the said supply line Wires to said circuit means.

2. In combination with a delta connected alternating current power supply line having load devices connected across phases thereof, a generator for producing signal impulses of frequency different from that of the alternating current on said supply line, a ground connection, means for coupling said generator between said ground connection and one or more wires of said supply line, said last means including means to interpose a high impedance to said alternating ourrent between said supply line wires and said ground connection, time controlled means for causing said generator to impress said signal impulses on one or more wires of said supply line through said coupling means, a synchronousmotor-operated time keeping device, means including a transformer for coupling said motor to one phase of said supply line, a receiver including circuit means selectively responsive to said impulses connected across the secondary of said transformer, for controlling said time keeping device, said receiver including circuit means selectively responsive to said impulses, capacitative means for coupling all 01 the wires of said supply line to one side of the secondary of said transformer, and means connecting the other side of said secondary to ground.

JOHN L. WAGNER. WASHINGTON WEBB. ROBERT N. EICHORN.

Name Date Dicke July 8, 1941 Number 

